The mission is too hard. Im Lv.40 and still I cant do it. I looked at guides but i die by the time 2/4 enemies die. Missions are the onlyy way to gain fast XP. Its really annoying. How do i complete it?
You should play more multiplayer... Once you level up a few times come back and blaze through them. You will get stuck eventually until you are a high enough level anyway. Final Boss is almost impossible until you have leveled up enough. I think I beat it around level 50/60 but it took so many tries and advanced strategy xD now I can just go in and reap them all without even really trying. Also keep in mind your aiming instincts will home in the more you play.